Integrated circuits are typically subjected to a “burn-in” process in which parts are stressed by applying various voltages and temperatures. These integrated circuits typically include transistors that have a “leakage current” that flows even when the transistors are turned off. Leakage current tends to increase with transistor junction temperature, and increased current in a transistor tends to increase the transistor junction temperature. When power supply voltages and temperatures are increased during burn-in, there may be a danger of thermal runaway that causes failure of good parts.